Theorem biexan1i ≪ | index | src | ≫

theorem biexan1i (c: wff) {x: nat} (a b: wff x):
  $ a <-> E. x b $ >
  $ a /\ c <-> E. x (b /\ c) $;

Step	Hyp	Ref	Expression
1		hyp h	a <-> E. x b
2	1	a1i	c -> (a <-> E. x b)
3	2	biexan1a	a /\ c <-> E. x (b /\ c)

Axiom use

axs_prop_calc (ax_1, ax_2, ax_3, ax_mp), axs_pred_calc (ax_gen, ax_4, ax_5)